Severe Storm Risk - Keystone, SD

There is a Marginal Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN PLAINS/UPPER MIDWEST...CENTRAL HIGH PLAINS...MIDDLE GULF COAST AND COASTAL CAROLINAS SUMMARY Severe thunderstorms capable of large hail and damaging wind gusts will be possible mainly this afternoon and evening across the Dakotas and northwest Minnesota as well as the central High Plains. Other severe storms may focus across the lower Mississippi Valley and middle Gulf Coast, as well as the coastal Carolinas. Dakotas/Upper Midwest to central High Plains An eastward-moving shortwave trough will emerge from the Canadian Rockies and move across the Canadian prairies through tonight, with a belt of moderately strong flow aloft and multiple MCVs influencing the Dakotas to Minnesota. Residual early day convection and lingering cloud cover will be complicating factors as far as the later-day forecast scenario. That said, at least widely scattered thunderstorms should develop and increase by late afternoon within a moist/unstable air mass near the eastward-moving front and weak surface wave across the east-central Dakotas and/or cross the international border and move southeastward into the region. Deep-layer wind profiles would be conducive to some supercells and the development of east/southeastward-moving clusters by evening, with large hail and damaging winds possible. More removed from the stronger cyclonic flow aloft, additional higher-based storms are expected by late afternoon and early evening south-southwestward across the Black Hills/western Nebraska in vicinity of the front and preceding trough. Sufficient strength/veering of winds with height should support some initial supercells capable of hail, prior to a clustering of these southeastward-moving storms, with wind damage being a possibility through mid/late evening across the central High Plains. Coastal Carolinas The region will be influenced by moderately strong cyclonic flow aloft, with a moist and moderate-to-strongly unstable environment along the coastal plain to the east of a stationary/slow-moving front. The degree of buoyancy and upwards of 35-40 kt effective shear could support some initial supercells with hail this afternoon, although damaging winds should be the most prevalent concern as storms become more numerous. Severe potential should tend to wane by around sunset. Lower Mississippi Valley/Middle Gulf Coast Widely scattered elevated convection has developed early in the overnight across the Ozarks, and this regime may increase and probably shift south-southeastward today, potentially becoming surface based into the afternoon, influenced by cold pool development. It seems plausible that an upscale-growing/forward propagating cluster could gradually evolve during the day, with damaging wind potential increasing across the ArkLaMiss south-southeastward toward the Gulf Coast. Northern Great Basin/central Rockies Scattered high-based thunderstorms are expected to develop this afternoon amid classic inverted-V profiles. Since these storms will develop along the periphery of stronger flow aloft, some organization is possible. Multiple dry microbursts may occur, some of which may pose a severe gust threat. Maine By late morning into early afternoon, partially clearing skies will encourage surface temperatures to rise into the 70s F, resulting in marginal instability (e.g. a few hundred J/kg MLCAPE) given relatively poor mid-level lapse rates. Nonetheless, a southerly mid-to upper-level jet streak will overspread northern New England during the afternoon, resulting in highly elongated hodographs and 30-40 kt of effective shear. As such, any storms that can develop and become sustained should become organized multicells capable of supporting a few damaging gusts and possibly some hail.